ext4: correct return value of ext4_convert_meta_bg

stable inclusion
from stable-v5.10.202
commit 3c1ad03a5ff20645ca67a84af8a078285fe20702
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I853YM

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3c1ad03a5ff20645ca67a84af8a078285fe20702



--------------------------------

commit 48f1551592c54f7d8e2befc72a99ff4e47f7dca0 upstream.

Avoid to ignore error in "err".

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Link: https://lore.kernel.org/r/20230826174712.4059355-4-shikemeng@huaweicloud.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Baokun Li <libaokun1@huawei.com>